This invention relates to implant insertion tools, and more particularly, to spinal implant insertion devices for insertion of implants into the intervertebral disc space.
Of interest are commonly owned copending application Ser. No. 09/705,377 entitled Spinal Intervertabral Implant filed May 3, 2000 in the name of Lawrence Shimp et al. and No. 60/246,297 entitled Spinal Intervertebral Implant Insertion Tool filed Nov. 7, 2000 in the name of Erik Martz et al. incorporated by reference herein.
Spinal implants, sometime referred to as grafts, are in wide use and typically comprise non-bone physilogically compatible metal or other non-bone materials or bone. Reference is made to the aforementioned copending application Ser. No. 09/705,377 for a bone implant. A similar type of implant disclosed therein is described herein in connection with FIGS. 10-13. What is desired is an implant insertion tool or device that is convenient to use, permits the surgeon to easily access the implant disc site in the patient and insert the implant in the desired orientation. The prior art is replete with implant insertion tools and devices.
For example, U.S. Pat. No. 5,782,830 to Farris discloses an implant insertion device. The device includes a handle, a shaft having a proximal end attached to the handle, and a distal end. A pair of jaws each having a first end is attached to the distal shaft end and a free second end. A gripping element is at the second end. The free ends of the jaws are movable between gripping positions to grasp the implant between the gripping elements and release positions to release the implant. The jaws are biased apart to the release positions. Each gripping element defines a substantially uniform or flat gripping surface that include teeth. A hollow sleeve is slidably disposed over the jaws for forcing the jaws together toward the gripping position.
U.S. Pat. No. 5,385,471 discloses a dental instrument comprising a grasping device in the form of a tweezer member having a finger receiving ring detachably connected to one of the legs of the tweezer member. The instrument is used to hold and insert a Cerec inlay in a tooth undergoing restoration.
U.S. Pat. No. 3,844,291 discloses a grip device in the form of a spring tubular pocket size device to grip and hold small things. The device includes a tubular body, a sleeve with a handle portion, a latch for supporting a spring and a cap or second handle member. Spring jaws are normally biased apart. A push rod is retracted and cam surfaces on a guide means urges the jaws inwardly to grip an object.
U.S. Pat. No. 4,877,020 to Vich discloses an apparatus for inserting a cylindrical externally threaded bone graft The instrument has an elongated handle, and a control rod extends axially through the handle and rotatably and threadably attached thereto. The control rod has a part which projects therefrom and releasably grips the implant.
U.S. Pat. No. 5,910,141 discloses a rod introduction apparatus for approximating a longitudinal member and an implant to permit fixation therebetween.
U.S. Pat. No. 5,946,988 discloses a tool for driving pedicle screws. The tool has clamping jaws secured to a shaft and a lateral projection tiltably received by one of the jaws. The tool has an axially slidable actuating member guided on the shaft.
U.S. Pat. No. 6,053,933 discloses a gripping unit for application in minimally invasive surgery. A stationary jaw is rigidly attached to a base section. A movable jaw is connected via a joint to a push/pull rod and an operating handle. The stationary jaw, the movable jaw, the rod and the base section have in the longitudinal direction a channel to receive additional instruments wherein the base section and rod form a circular conduit.
U.S. Pat. No. 6,099,483 discloses a jaw assembly for an endoscopic instrument. which includes first and second end effectors, a screw, and optionally a washer. The end effectors have arms biased apart. The screw has a threaded portion engaging the distal end of the instrument and a head portion with a pair of arm receiving grooves. The arms are captured between the screw and washer. The grooves are provided with upstanding pins which engage mounting holes in the arms.
U.S. Pat. No. 6,099,550 discloses a surgical instrument having jaws biased apart and an operating channel and method for use thereof. The instrument includes a forceps unit for positioning within an anatomical cavity. The forceps unit has a housing, an outer tubular member, an intermediate tubular member and a handle mechanism for creating relative movement between the intermediate and outer tubular members. The outer tubular member has a proximal end mounted by the housing and terminates distally at a distal end. The intermediate member has a tubular body disposed telescopically within the outer member. Relative movement of the outer tubular member over the jaws causes the jaws to close.
U.S. Pat. No. 6,174,311B1 discloses an interbody fusion grafts and instrumentation. Implants similar to the implant described herein are disclosed and instrumentation for insertion of such implants are also disclosed. One implant holder includes a handle, a gripping head a first branch and a second brand pivotally attached to the first branch with a pivot pin. The gripping head includes a first gripping arm integral to the second branch and a second gripping arm integral to the second branch. A recess cavity is formed between opposing gripping arms. The gripping arms include projections which matingly engage first and second indents on the implant. The gripping head includes a surface for contacting the tool engaging end of the implant to drive the implant into a preformed cavity. The gripping arms include impacting surfaces. One gripping arm remains stationary and the other pivots about the pivot pin. A locking pin prevents pivoting of the second branch. the implant is released by disengaging the locking pin. The implant is C-shaped or J-shaped for implantation in the intervertebral disc space.
A second embodiment of a implant holder tool is also disclosed. It has a gripping head and a handle for releasably securing and impacting the implant duirng insertion. The gripping head includes a roughened impacting surface orthogonal to the insertion direction. The gripping head includes a first surface orthogonal to the impacting direction and a second surface inclined to the impacting direction. In addition a shaft extension secures the implant to the gripping head.
U.S. Pat. Nos. 5,797,909, 6,083,225, 6,080,155 and 6,096,038 disclose still other instrumentation for inserting spinal implants.
An implant insertion tool according to the present invention comprises an elongated shaft having a longitudinal axis and proximal and distal ends, the shaft having a bifurcated distal end forming first and second shaft portions arranged to flex toward and away from each other in a direction generally normal to the axis. A handle is at the proximal shaft end and an implant gripping extension extends from each the shaft portion in a distal direction for gripping an implant therebetween. A displacement member is attached to the shaft portions for displacing the first and second portions relative to each other in the generally normal directions toward and away from each other. A stop member is secured to the portions for limiting the maximum distance the shaft portions and extensions can separate.
In one aspect, the displacement member comprises a threaded stud, a smooth surface circular cylindrical shank attached to the stud and a knob attached to the shank distal the stud, the shank for rotatable attachment to the first shaft portion and the stud for threaded engagement with the second shaft portion, the shank, knob and stud being dimensioned to capture the second portion between the stud and the knob.
In a further aspect, the stop member comprises a shank and a head attached to the shank, the end of the shank distal the head being threaded to one of the shaft first and second portions and the head engaged with the other of the shaft first and second portions, the head being larger than the shank for capturing the other of the shaft first and second portions thereto.
In a further aspect, the normal quiescent position of the extensions is arranged to receive the implant therebetween such that rotation of the knob closes the spacing between the extensions to grip the implant.
Preferably the stud has a diameter greater than that of the shank.
In a further aspect, the displacement member comprises a threaded stud attached to the first shaft portion, a shank attached to and passing through the second shaft portion and a knob attached to the shank, the knob, shank and stud being arranged to capture the second member to the shank.
In a further aspect, the tool according to the present invention comprises an elongated shaft having a longitudinal axis and proximal and distal ends, the shaft having a bifurcated distal end forming first and second shaft portions arranged to flex toward and away from each other in a direction generally normal to the axis. A handle is at the proximal shaft end. An implant gripping extension extends from each shaft portion in a distal direction for gripping an implant therebetween. A displacement member is attached to the shaft portions for displacing the first and second shaft portions relative to each other in the generally normal direction toward and away from each other, the displacement member comprising movable displacement means having first and second positions for forcing the shaft portions apart in the first position for receiving and releasing the implant and for forcing the shaft portions together to an implant gripping state in the second position.